Hs200 failed a few months ago and it was less than 3 years old. Switch would click and strobe light off and on. Removing it and resetting it didn't fix it. Replaced under warranty. 
 

tonight one of my HS210 switches started doing the same thing. I have about 10 switches all the same age. Now I worry they all will fail. 
 

it took TP-link weeks to just look at my case. 
 

Any ideas other than replace it and hope the others don't fail? I use these as timers and when they fail the neighbors probably wonder if there is an emergency due to the flashing.  When they fail, there is no way to turn it off other than remove it.